%I #7 Sep 08 2022 08:46:17
%S 431,443,683,65963,4294967723
%N Primes of the form 2^(2^n) + 427.
%C Terms given correspond to n = 1, 2, 3, 4 and 5.
%C Next term >= 2^2^27 + 427. - _Charles R Greathouse IV_, Jun 07 2016
%t Select[Table[2^(2^n) + 427, {n, 0, 15}], PrimeQ]
%o (Magma) [a: n in [0..16] | IsPrime(a) where a is 2^(2^n)+427];
%o (PARI) for(n=1,5, if(ispseudoprime(t=2^2^n+427), print1(t", "))) \\ _Charles R Greathouse IV_, Jun 07 2016
%Y Cf. similar sequences listed in A273547.
%K nonn
%O 1,1
%A _Vincenzo Librandi_, Jun 02 2016